small, deep aluminum hole

[Hoeken]

hey all,

i'm involved in the RepRap project, and have some metal working questions. to construct our extruder nozzle, the process is to take a 3" x 3/8" aluminum hex head bolt and drill out a 3" deep 1/8" hole through the bolt.

Currently, I'm using a drill press + clamp + long series drill bit. This worked well for me, but it did take a bit of time as i had to keep bringing the bit out and cleaning it. I used a generic 3 in 1 oil for lube / coolant. What are the 'best' practices for this type of drilling? What is the ideal lubricant to use?

Keep in mind that one of the goals for the project is to keep costs down... so suggestions like 'get a $5000 foobar' dont really help. assume the person will have access to an average shop... with a drill press being the upper limit to the types of tools available. (no lathes, etc)

[RICHARD ZASTROW]

Hoeken, Please don't misunderstand. If the project can't afford proper equipment, maybe somebody will do it for you at nominal cost. That same hole has been drilled on lathe many times. Better yet, maybe somebody with a gundrill will do it for you. Otherwise you will have to spend the time on your upper limit drill press.

[Hoeken]

no worries. perhaps i should clarify a bit: i have already attempted and successfully drilled the hole with my drill press, but I was just wondering if there were any tips or things I could do to optimize the process before taking it to the next level.

[RICHARD ZASTROW]

Hoeken, If there is any volume in "the next level", a gundrilling vendor should make short work of your long hole for a $hort invoice.(pun intended)

[Geof]

If you insist on doing it the drill press way one method to keep the hole better centered is to hold the work in the drill chuck and hold the drill in a fixture on the table.

If you get a second drill chuck with a threaded hole for mounting, like are used on electric hand drills you can drill a hole in the drill press table, bolt your second chuck in this hole. Grip your work in the main chuck, use a spot drill to start the hole and then drill. This will be easier for doing several bolts.

[InspirationTool]

Ayup, spin the work, not the drill. It will walk less, and gravity will be your friend.

-Jeff